% \documentclass[preview]{standalone}
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\documentclass[draft]{beamer}
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\usepackage[size=custom,height=10,width=25,scale=0.7]{beamerposter}
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\usepackage[braket, qm]{qcircuit}
\usepackage{amsmath}
\pdfmapfile{+sansmathaccent.map}
% \usepackage[landscape]{geometry}
% Comment out the above line if using the beamer documentclass.
\begin{document}

\begin{equation*}
    \Qcircuit @C=1.0em @R=0.2em @!R {
	 	\lstick{ {veryLongQuantumRegisterName}_{0} :  } & \gate{\mathrm{H}} & \gate{\mathrm{H}} & \gate{\mathrm{H}} & \qw & \qw\\
	 	\lstick{ {veryLongQuantumRegisterName}_{1} :  } & \gate{\mathrm{H}} & \gate{\mathrm{H}} & \gate{\mathrm{H}} & \qw & \qw\\
	 	\lstick{ {veryLongQuantumRegisterName}_{2} :  } & \gate{\mathrm{H}} & \gate{\mathrm{H}} & \gate{\mathrm{H}} & \qw & \qw\\
	 	\lstick{ {veryLongQuantumRegisterName}_{3} :  } & \gate{\mathrm{H}} & \gate{\mathrm{H}} & \gate{\mathrm{H}} & \qw & \qw\\
	 	\lstick{ {q0}_{0} :  } & \qw & \qw & \qw & \qw & \qw\\
	 }
\end{equation*}

\end{document}